Jan. 26, 2010
CONTACT: Gordon Ovenshine:
Researchers fish for answers
SLIPPERY ROCK, Pa. ��- There is something positively fishy going on at Slippery Rock University - a student-faculty research team in biology is making discoveries about the sophisticated behavior of cichlid fish.
For instance, the brightly colored fish, which are native to Central and South America, greet each other and form partnerships. They defend their young; respond to scents, and males show a preference for a particular body type in females, said Simon Beeching, professor of biology. "Parental care of any kind is extremely rare in fish," he said.
The findings stem from research involving Beeching and Jessica Rack, a biology major from Daybrook, W. Va., and Kimberly Wilson, a biology major from Macomb, Mich. They are raising and studying convict and firemouth cichlids kept in freshwater tanks.
Cichlids are one of the largest families of freshwater fish, with more than 2,000 species. Many are very colorful and common in home aquariums. Firemouth cichlids have red throats and bellies. Convict cichlids are marked by black stripes.
Beeching said the researchers are interested in the evolutionary reason why the species exhibits such usual behavior. Evolution assumes species change over time to adapt to a specialized environment, with adaptations increasing the success of the species. SRU's researchers say they are beginning to reach conclusions.
"What is very interesting about them is they exhibit very sophisticated social interaction," Beeching said. "They form pair bonds. Males and females work together to raise their young. In some cases they will defend the young and will also do brood adoption, adopting fish that are not their own. At an evolutionary level, the idea is there is safety in numbers. In their particular ecological environment, parental care pays."
One of their original discoveries involves males' preferences in a mate. Beeching said males choose the largest female available because it helps to propagate the species.
"It turns out that the key criteria is not color, but that males universally prefer to mate with the largest female available," he said. "The reason is big females lay more eggs, so they leave you more offspring." Females look for a male that is slightly larger than they are, not the biggest fish in the sea, he said.
Not all fish follow the same patterns because it doesn't help them survive. "In evolution, there are fundamental answers for behavior that evolve when the benefits outweigh the costs," Beeching said. "Not all fish care for their young, because it costs time to keep looking after your young, when you could be eating or making more young or finding a mate."
Rack is examining the convict cichlid's behavioral responses to scents and visual cues. She exposes the fish to scents of other fish and a dummy fish shaped and painted to look like a convict cichlid. She videotapes the fish for 20 minutes to see how much time they spend in proximity to the dummy fish and the scent.
"This work is important in determining the presence of a chemical communication system in this species of fish," she said. "While animals living on land rely heavily on vision to avoid predators and find mates, visual signals can be compromised in an aquatic environment, leading to reliance on other senses. Our research shows that some cichlids do respond to olfactory cues in several contexts."
Rack, who plans to present her findings at the National Conference on Undergraduate Research, said she finds the research fascinating and is thankful to SRU for the opportunity.
"One of the best things about Slippery Rock University is its small size, and the personal attention that students receive as a result," she said. "I have been able to work one-on-one with a professor that I respect and admire, and I have received a student-faculty research grant that has allowed me to complete my experiment and travel to a national conference to present in April. SRU has allowed me the space to grow. I will graduate in May with a strong resume and the competitive edge gained from this experience."
Wilson said she is researching the behavioral significance of color patterns found on firemouth cichlid. She presents the fish with two dummies simultaneously in what is called paired dummy presentation to gauge their reaction.
"This work is important because while there have been some field studies on the variable color patterns of firemouth cichlids, little work has been done involving the black color patterns," Wilson said. "Any time scientists have the opportunity to learn something new about animals always helps us to better understand the world around us."
Wilson, who plans to become a veterinarian, said she expects the research to be an invaluable experience. "I am extremely grateful to SRU and Dr. Beeching for giving me this wonderful opportunity to conduct a research project," she said. "Even though we are just beginning our work, I already feel that I have learned so much. The skills I am learning now will be very beneficial to me in my future career, and I am enjoying learning about firemouth cichlids and dummy making."
Beeching said he takes the holistic approach to research projects with undergraduates, requiring them to experience the entire process.
"I require them to participate in every step," he said. "That means grant writing and doing the paperwork to meet the institutional regulations regarding the use of animals. They have to go through training, do data analysis and present at conferences. My approach is to show them everything, including scientific writing and oral presentation."
SRU's Symposium for Student Research, Scholarship and Creative Acvitity will be April 8-9. Student abstracts will be accepted through Feb. 5.
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